1. Field
This invention relates to surgical instruments and more particularly to devices for inserting drains and the like.
2. State of the Art
The technique of arthroscopic surgery has been developed for use particularly with knees and shoulders, to minimize the incision and disruption of the joint during extensive repairs to various parts of the joint including ligaments and cartilage. During these procedures, as in many other surgical procedures, it is often necessary to insert a tube into the affected body part to drain fluids which would otherwise accumulate. It is desirable to perform this procedure in a manner causing the least possible damage to other nearby tissues and internal structures. In arthroscopic knee surgery, for example, it is highly desirable to avoid damaging the articular cartilage.
The standard trocar used for insertion of a drain in arthroscopic procedures is an elongated member with a circular cross-section having a bend or angle along its length and a sharp forward point for piercing sacs or cavities in which fluid collects. The drain itself is usually a piece of flexible tubing having one end hooked to a device for aspirating the interior of the tubing. The other end of the tubing may be connected to the rear end of the trocar, by fitting snugly over a threading or by other removable means.
In use, a standard trocar with drain tubing attached is inserted into a surgical incision. The surgeon maneuvers the trocar using a wrench-like tool to grip the rear end of the trocar, until the tip is adjacent a boundary membrane of the sac whose drainage is desired. Force is then exerted to urge the trocar point to pierce the sac, and to push it until the trocar pierces the skin to exit the limb approximately on the opposite side from the incision. The surgeon then grips the trocar tip with the same or similar wrench-like tool, pulls the trocar out of the exit cut, and detaches the tubing from the rear end of the trocar, usually by pulling the tubing in the rearward direction. The end of the tubing is then pulled back into the limb until it is positioned within the sac.
The above-described trocar and method of placement of a drain during arthroscopic procedures have several disadvantages. First, the exposed tip of the trocar can cause injury to the tissues inside the joint as it is inserted through the arthroscopic incision and is maneuvered to the sac. Standard trocars have an angled shank designed to follow a curved path within a hip joint, whereas with knee or shoulder joints it is usually desirable to pass the trocar in a straight line, to facilitate pushing the trocar to pierce the sac and to exit the limb. Manipulation of the trocar is performed using a wrench or pliers-like tool to grip the trocar's proximal end, which is prone to slippage since the trocar end typically has a circular cross-section. Slippage of the grip on the trocar is a particular problem when force is exerted to push the trocar through otherwise intact body tissue. The standard trocar is also relatively short in length, further increasing the difficulty of grasping and maneuvering with the tool.
Moreover, removing the trocar as it exits the joint is also problematic. The forward end of the trocar must be gripped with a tool to pull it free from the exit wound. However, the trocar presents a smooth exterior on which it is difficult to maintain a grip when the necessary force is applied to pull on the trocar. The gripping tool is thus prone to slip free, or the trocar may fly loose from the tool as it is pulled from the exit wound, and cause injury to nearby personnel. Also, the surgeon's hand can slip and be punctured by the trocar point. Such punctures carry the risk of transmission of the HIV (AIDS) virus, hepatitis virus, or other serious infectious microorganisms. Thus, it is especially desirable to avoid even minor punctures.
Accordingly, a need remains for a surgical trocar for insertion of drains which provides improved ease of manipulation and protects the patient from unnecessary damage to tissues adjacent the incision.
Additionally, there is a further need for a trocar having means to facilitate its removal from a patient's exit wound. It is particularly desirable to have such trocar removal means which will prevent accidental punctures to medical personnel.